The present invention generally relates to remote copying and power saving.
A remote copy system, which is configured from a plurality of storage controllers and a plurality of storage devices at a local site, and a plurality of storage controllers and a plurality of storage devices at a remote site, is known (Hereinafter, the storage controllers and storage devices at the local site will be referred to as the “local controller” and the “local storage device”, and the storage controllers and storage devices at the remote site will be referred to as the “remote controller” and the “remote storage device”.).
In the remote copy system, the local controller reads out data from the local storage device and transfers this data to the remote controller, and the remote controller receives the data from the local controller, and writes the received data to the remote storage device. In other words, data stored in the local storage device is remote copied to the remote storage device.
Data to be remote copied, for example, includes data that configures a snapshot. The local controller, for example, acquires a still image of a file system at a certain point in time as a snapshot. The local controller can manage a plurality of generations of snapshots (that is, still images of a plurality of points in time).
Japanese Patent Application Laid-open Number 2007-193451 (hereinafter referred to as Patent Document 1) discloses technology that remote copies data that configures a snapshot.
It is preferable to reduce the power consumption of the remote copy system. As one method for achieving this, a method that puts the local controller and/or the remote controller in a power-saving mode when not carrying out processing related to a remote copy can be considered. However, since there is normally no way of telling when the local controller will receive an access command (a write command or read command) from a higher-level device, it is probably not preferable to put the local controller in the power-saving mode even if the local controller is not engaged in remote copy-related processing. Accordingly, putting the remote controller in the power-saving mode (for example, a state in which the power is turned OFF) while not carrying out remote copy-related processing (receiving data, or writing received data) is considered.
Meanwhile, for example, a remote copy system in which a plurality of virtual computers operate in the local controller and the remote controller can be considered. In this case, the exchange of remote copy-targeted data is carried out between virtual computers (hereinafter, a virtual computer running on the local controller will be referred to as the “local virtual computer” and a virtual computer running on the remote controller will be referred to as the “remote virtual computer”.).
When a plurality of remote virtual computers exists in a certain remote controller or a remote controller group, for example, even if a certain remote virtual computer is in a non-operating mode (is not engaged in processing related to a remote copy), if another remote virtual computer is in an operating mode (is engaged in processing related to a remote copy), it is not possible to put this certain remote controller in the power-saving mode. Further, for example, for a remote controller in the power-saving mode, if a certain remote virtual computer does not have to be in the operation mode but another remote virtual computer does have to be in the operating mode, this remote controller will have to be released from the power-saving mode.